Search Documents

By Earl C. Redman

The Juneau Gold Belt, centered on Juneau and approximately 120 miles long by 10 miles wide, stretches from Berners Bay on the north to Windham Bay on the south (fig. D-l). Access within the Juneau Gold Belt is provided by the Glacier, Thane, and North Douglas Highways. The Glacier Highway extends northwest from Juneau for approximately 40 miles to Echo Cove, and the other two roads end 5.5 miles southeast and 12.6 miles west from Juneau, respectively. None of these roads connect with other highway systems and access to other areas is restricted to airplanes, the State ferry system, and commercial barge lines. BUREAU ACTIVITIES The majority of lode gold produced in Alaska came from the Juneau Gold Belt portion of the Juneau Mining District. To evaluate the economic potential of the Gold Belt, the Bureau located 173 mines and prospects within the area. A total of 263 ad its and shafts were found and 56,650 feet of underground workings were mapped. The Bureau collected and analyzed 1,557 samples during the study. In addition, considerable detailed geologic map-ping was done in the vicinity of the mines and prospects from which ore control models were developed.

Jan 1, 2012

By Koehler Stout

Previous work done by the authors of this report indicates that hydraulically-placed backfill can be strengthened several fold by various placement methods. Sunshine mill tailings were tested by these placement methods and strength increases up to thirty times were achieved over the ordinary placement methods. A computer simulation study of the test stope in the Sunshine Mine showed that a high-modulus fill absorbs up to 27% of normal stresses versus 7% for "normal" fill while reducing maximum convergence 28% versus 8% for "normal" fill. Although high-modulus fill was not placed in the test stope during this contract, various instrumentation was purchased, designed and built to record necessary data in the stope. Stress gauges were placed in the pillars and recorded data corresponded quite closely with theoretical projections.

Jan 1, 1983

By Florence L. Feicht, Carlton E. Brown

"INTRODUCTION This report contains information on the approximate size of the smallest dust Particles revealed by or the limit of visibility of various microscopic systems. The information was obtained mainly for use in interpreting and evaluating results of number-contentration and particle-size, determinations on, samples of unhygienic particulate matter collected from industrial atmospheres and in developing better methods for determinations nations.Some speculation and even controversy have been published on the limit of visibility of the widely used microscopic system (16-mm., 0.25-or 0.3-N.A. objective, and axial light-field illumination) used in counting the dust in the liquid medium from impinger, 4/ 5/ filter-paper, 6/ and other samples, but little or no quantitative data have been published on the limits of visibility of this or other microscopic' system.ACKNOWLEDGMENTSThe interest, encouragement, and assistance received from H. H. Schrenk, chief of the Health Division are gratefully acknowledged, as is all other assistance received in this study."

Aug 1, 1945

By George H. Holmes

Beryllium deposits in the northern Virgin Mountains , Clark County , Nev . , and Mohave County , Ariz . , about 70 miles northeast of Las Vegas , were investigated by the Bureau of Mines . The investigation indicated a widespread occurrence of beryllium- bearing pegmatites within an extensive belt of mica - schist . Several deposits with significant beryllium mineral concentrations were encountered . Only a few of the samples analyzed contained more than 1 percent beryllium oxide ( BeO ) ; in many of the samples , no beryllium was reported . The average tenor of samples from the more important occurrences was 0.25 percent BeO . Chrysoberyl is the predominant beryllium mineral in the pegmatite sills ; beryl predominates in the more massive bodies . Minute quantities of cesium and lithium minerals also occur , but no columbium , tantalum , or other rare minerals were found . Ore dressing tests on a composite sample containing 0.28 percent BeO which was representative of the pegmatite sills , indicated an 85 percent recovery of the chrysoberyl ( 70 percent recovery of total BeO ) by gravity concentration in a concentrate containing 17.6 percent BeO .

Jan 1, 1964

By W. W. Adams, T. D. Lawrence

"The National Safety Competition covering the calendar year 1934 was the tenth yearly safety contest conducted by the United States Bureau of Mines. Participating in the competition were 334 mines and quarries in 38 States. Five mining or quarrying companies, each the leader in its group for having established the best safety record during the year, were awarded the national safety trophies ""Sentinels of Safety.""Since these annual contests were begun 10 years ago by the United States Bureau of Mines the scope of the competition has been broadened materially, both as to the number of plants participating and as to the number of man-hours of exposure to accident hazards. Moreover, marked progress in the prevention of accidents has been achieved, as is indicated by an almost constant downward course in toe accident-frequency rates for the contest group as a whole during the past 10 years. On the other hand, the accident-severity rates for the group showed an upward trend during the first part of the decade and a downward trend during the latter part of the period except in 1930 and 1934; in each of those years a disastrous explosion with abnormally heavy loss of life occurred at the property of one of the participating companies.Because of the abnormal nature of the major disaster in a bituminous-coal mine in 1930 and 1934 the accident-severity rates for the bituminous group for those years are not strictly comparable with the rates for other years. The rates for bituminous mines for 1934 in the present report have therefore been computed on two bases; first, to exclude the record of the company that suffered the disastrous explosion and, second, to include the record of this company. The first rate represents the normal experience of the bituminous coal companies unaffected by the disaster and is therefore more indicative of the real trend of the accident rates for this class of mines from year to year. The latter rate shows the actual experience of all bituminous mines in 1934. The report of the competition of 1930 likewise showed the rates for the bituminous group as computed both with and without the disaster that occurred that year.The National Safety Competition is conducted by the United States Bureau of Mines in the interest of safety in the mining and quarrying industries. This object is accomplished directly through the efforts of the competing companies and their employees to win first place in the competition and thereupon receive well-merited and national recognition for their achievement. Indirectly the purpose of the contest is accomplished through studies by the Bureau of Mines of the facts contained in the accident reports which the competing companies furnish to the Bureau to enable the Bureau to compute the accident rates that are the basis for determining the winners of the contest."

Jun 1, 1935

By Michael E. Henderson

Presented in this report are the experimental results of coarse coal slurry degradation data obtained from the Hydraulic Transport Research Facility (HTRF) at the Pittsburgh Research Center (PRC), Bruceton, PA. The facility is operated by Boeing Services International, under Bureau of Mines Contract No. J0333956. Presented in this report are the experimental results of coarse coal slurry degradation data obtained from the Hydraulic Transport Research Facility (HTRF) at the Pittsburgh Research Center (PRC), Bruceton, PA. The facility is operated by Boeing Services International, under Bureau of Mines Contract No. J0333956. This particle degradation report is a summary of the particle distribution data obtained at the HTRF for the period 26 November 1982 to 1 October 1983. The testing covered herein is for coarse Pittsburgh Seam coal in the 6-in (150 mm) and 12-in (300 mm) pipelines, at velocities ranging from 5 to 18 ft/s (1.5 to 5.5 m/s), and at concentrations by weight ranging from 15 to 55 pet. Particle size distribution samples were taken systematically throughout the testing.

Jan 1, 1985

By George L. Gates

This report presents is an evaluation by the Federal Bureau of Mines of the effect of clay-water, brine, and oil-base drilling fluids on the productivity of test wells drilled on the Umiat anticline in U.S. Naval Petroleum Reserve No. 4 in northern Alaska. Eleven, wells were drilled on the Umiat structure as part of the U.S. Navy's extensive exploration of the Reserve during 1944-53 to determine the possibilities for oil production. The Federal Geological Survey cooperated in the exploration program and has published a comprehensive report3/ on the geology of the area and case histories of the wells. The re¬port also includes the results of special studies by the Bureau in connection with the drilling and coring of well 9 with oil-base mud in hole and was the source of much of the information used in preparing this publication. Of the eleven wells, four were drilled with rotary tools and water-base mud (one of the water-base muds was an oil-in-water emulsion mud), five were drilled with cable tools with brine in the hole, one was drilled with cable tools with brine in the hole and later reamed with rotary tools and crude oil, and one was drilled with rotary tools and oil-base mud. Although all of the wells penetrated sandstones that contained oil and gas, some were productive and others were not. The latter two wells, one completed with crude oil in the hole (with some added brine) and the other with oil-base mud, had the greatest productive capacities. The wells drilled with cable tools and brine in the hole had lower productive capacities. In contrast, two of three wells completed with rotary methods and fresh-water drilling mud and the well com¬pleted with rotary and emulsion mud were unproductive.

Jan 1, 1960

By D. E. Shanks

As part of its goal to help maintain an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines, U.S. Department of the Interior, is investigating a fused-salt electrolytic procedure for producing zinc metal. A previous report described preliminary, small-scale work on the fused-salt electrolysis of ZnC12. The present report covers a more detailed investigation of the properties of ZnC12-alkali metal chloride electrolyte systems in relation to the production of zinc metal and also discusses electrolysis in largescale, internally heated cells. The effect of composition on bath stability, current efficiency, cell voltage, and liquidus temperature was determined for the ZnCla-NaC1-KC1, ZnC12-NaC1-LiC1, and ZnC12-KC1-LiC1 electrolyte systems. An electrolyte com-posed of 38 mole-pct ZnC12, 31 mole-pct NaC1, and 31 mole-pct KC1 gave the best overall results. Sludge (ZnO) formation in the ZnC12-NaC1-KC1, ZnC12-KC1-LiC1, and ZnC12-KC1 systems was investigated during prolonged electrolysis. The ZnC12-KC1-NaC1 electrolyte showed the least sludge formation. A 1,500-amp cell was operated using the ZnC12-NaC1-KC1 electrolyte at 500° C. Zinc metal was produced at the rate of 4.0 lb/hr with a current efficiency of 95 pct.

Jan 1, 1979

By George L. Gates

It is generally recognized that if the lose and contamination of the fluid content of a core specimen from an oil- and gas-bearing formation in a well were eliminated, the value of core analysis would be increased greatly. In an effort to obtain uncontaminated cores, extensive field tests were carried out in the Mercy field, San Jacinto County, Tex., with the Carter pressure core barrel and an oil-base drilling fluid having very low rates of filtration as measured by the standard A.P.I. drilling-fluid filter teat. A tracer was added to the drilling fluid filter test. A tracer was added to the drilling fluid to provide a means for quantitatively measuring the volume of oil filtrate in the cores. Unfortunately, as stated in the report on the Mercy tests, very little oil nand was penetrated in coring the well; and because the performance of the pressure core barrel was not entirely satisfactory, the tests did not provide a complete answer to the question: Does a filtrate from an oil-base drilling fluid enter cores., and how does it affect the results of the core analyses?

Jan 1, 1950

By Michael E. Henderson

The U.S. Bureau of Mines (BOM) constructed the Hydraulic Transport Research Facility (HTRF) to investigate the hydraulic parameters relating to the transport of coarse coal. To achieve these goals in a timely and efficient manner, the Bureau contracted to Boeing Services International, Inc. (BSI) the responsibility of operating the HTRF and providing technical support. This data report is a summary of the testing and data results for the period from 6 September to 9 September 1983. The testing covered herein is for coarse 2-in by 0 (minus 50 mm) Pittsburgh Seam run-of-mine (ROM) coal in a 12-in (300 mm) pipeline, at velocities ranging from 8 to 16 ft/s (2.4 to 4.9 m/s) and at concentrations ranging from 15 to 50 pct.

Jan 1, 1985

By Kenneth H. Johnston

This report describes an in situ combustion project and three waterflood projects in Allen, Anderson, and Wilson Counties, Kansas, that will be visited during the 1964 annual tour of the Kansas-Oklahoma Waterflood Association. Among the unique features of the projects are the movement of heavy crude oil through the reservoir and into the wellbore with energy furnished by burning s portion of the crude oil therein. Another feature is the simultaneous injection of C02 and water, through separate tubing into input wells during early development, to increase injectivity at moderate pressures, Discussion of individual projects includes information on their early history, source and treatment of injection fluids, oil production-decline curves, and the results of water injection on oil production.

Jan 1, 1964

By James A. Browning

Conventional flame channelling operates continuously at over 120 db --flame-drill channelling at a maximum of 95 db. The latter process was developed under this program. Individual drill holes are spaced to leave narrow rock webs. Sound and dust passing from the hole are effectively treated by a muffler and water injection.

Jan 1, 1980

By William J. Krisko

This contract final report summarizes the design, fabrication and testing of a "line brattice air curtain" device under Bureau of Mines Contract H0357097. The purpose of this program was to develop the concept of using an air curtain for coursing ventilating air parallel with the air curtain From the last open crosscut to the face in exhausting ventilation systems to replace the line brattice cloth in room and pillar coal mining operations. The final design of the air curtain device consists of a 10-foot long closed end pipe with c: slot cut along its length. Pressurized air is delivered to the open end with a hydraulically-driven blower. A sheet of air emanates from the slot and is directed toward the mine roof. An invisible sheet of air is thus created between the top of the machine and mine roof and acts a an extension of the existing conventional line brattice.

Jan 1, 1977

By Mackenzie Burnett

The Brattice Window Method was used to measure the leakage rates of a total of 42 ventilation stoppings in 8 hardrock mines. Various types of stopping construction were evaluated. The following types are listed in order of decreasing effectiveness: 1) Cinder block, 2) Timber and mortar, 3) Timber and polyurethane foam, and 4) Timber and brattice material. There are slight differences in the effectiveness of the first three types, while the timber and brattice type is substantially inferior to the others. The repeatability of the Brattice Window Method was found to vary with physical conditions in the mine such as stopping location with respect to intersections, regularity of drift cross section, and the presence of hardware such as air and water pipes, timber sets and wire mesh. The Brattice Window Method is viewed primarily as a tool for estimating and comparing stopping leakages for the purpose of determining where repair efforts should be concentrated. A laboratory test program resulted in the derivation of several "rules of thumb" for employing the Brattice Window Method, which will aid in securing accurate and repeatable data.

Jan 1, 1979

By Richard F. Link

A statistical technique, useful to analyze assay and other data characterized by location in three dimensions, is described in this Bureau of Mines report. If present, trends in the data are defined for the purposes of improving ore estimation, predicting ore beyond existing workings, and aiding geological interpretation. The technique is to fit linear and quadratic polynomial equations to the data through the statistical method of regression analysis. The fitted linear equations have the geometric form of hyperplanes; the fitted quadratic equations have the geometric form of ellipsoids or elliptic hyperboloids of one or two sheets. To visualize these three-dimensional forms, contour maps of a series of plane sections through the fitted surfaces are plotted. Both the fitting of the polynomial equations and the plotting of the con-tour maps are done by electronic computer to facilitate calculations and to obtain accurate results. Computer programs are described in appendixes. Methods employed are illustrated by an example analysis) based on data from a part of the Fresnillo mine) Zacatecas, Mexico.

Jan 1, 1966

By C. M. Mason

The methods currently used by the Bureau of Mines to evaluate the sensitivity, strength, incendivity, gaseous products, and physical properties of explosives and hazardous chemicals are described. Included are the tests used to evaluate explosives which arc certified as permissible for use in underground coal mines.

Jan 1, 1972

By D. F. Walsh

A study of damping capacity was made on a number of magnesium-base alloys, commercial types and experimental compositions. Hardness and tensile properties were determined, and the microstructure of each alloy was examined. Alloys of low yield strength, in general, possessed high damping ability. A correlation was established between damping capacity and composition.

Jan 1, 1962

By John J. Sammarco

This report details the testing and evaluation of a modular azimuth and positioning system (MAPS) to provide navigational information for a continuous mining machine. Vehicle navigation is part of the U.S. Bureau of Mines research program in computer-assisted mining serving as a tool to increase mining health, safety, and productivity. The Bureau is investigating other navigation systems, but MAPS seems to have the most promise. MAPS was installed on a continuous mining machine. An operator used the machine to cut coal while researchers collected machine and MAPS data. A comparison of MAPS data for xy position and data obtained with an electronic transit showed an increasing error for MAPS. After 30 min of operation, the easting position error was -0.02 m, and the northing position error was 0.019 m; after 60 min of operation, the easting position error was -0.19 m, and the northing position error was -0.26 m. Modifications to MAPS software and to the operational procedure of the machine significantly reduced this error by a factor of 3.7. Researchers continue to reduce these errors.

Jan 1, 1993

By Bruce I. Thomas

As a part of the United States Department of the Interior program for developing natural resources in Alaska, the Bureau of Mines studied the tin-bearing gold-placer deposits in the Tofty area of the Hot Springs district in central Alaska. The principal objective of the Bureau's work was to obtain facts about the extent and character of the placer deposits (including tailing) to indicate the economic or strategic tin-production potential of the Tofty "tin belt." A secondary objective was to determine (if possible) the bedrock Source of the cassiterite and other minerals found in the placer deposits. The placer phase of the work was begun in July 1954 and was continued during the 1955 and 1956 field seasons. Extensions to, and connections between, known placer channels were sought by 82 churn-drill holes. The Bureau drilling did not expand the placer deposits beyond the limits established by drift-mining operations and by previous drilling done by private concerns.

Jan 1, 1957

By V. A. Danielson

The Bureau of Mines studied waste disposal methods a1 a coal mine in Kentucky and another in Alabama to develop cost estimates, to provide better knowledge of current practices, and to guide consideration of alternate disposal methods. Costs of the existing waste disposal systems at each mine were estimated using present-day costs of equipment and labor. Costs of waste disposal systems using alternate equipment were also estimated. Although total disposal costs were essentially the same for both operations, reclamation costs will differ because of different reclamation practices.

Jan 1, 1969